Several devices and methods have been used in the past to collect, preserve, transport and dispense chemical, environmental or biomedical specimens including fecal samples for later analysis by a laboratory or for clinical studies. The most common Guaiac Dye Test has been a smear paper pad, upon which, in the case of fecal samples, three consecutive specimens are smeared with dietary restrictions, covered then sent for analysis. One of the most common problems associated with this hundred years old device and method is dehydration. Even under rehydrating conditions, a fecal occult blood test of dry samples on paper pads will give a high rate of false positive or negative results. A false positive result may trigger a relatively expensive colonoscopic or barium enema examination that will probably or eventually eliminate the false diagnosis. In the case of a false negative result, an early stage colorectal cancer may be missed, and if then metastasis occurs, the cancer may become incurable.
Another fecal sample collection device of the prior art comprises a simple cylindrical tube with a cap having a breakable tip and a plastic stick connected to the inside of the screw cap. The tube contains a certain amount of extraction buffer. The stick is inserted into fresh feces several times then put back into the tube and the cap is tightly secured to seal the tube. The main advantage of this procedure is that the extraction buffer keeps the specimen wet and a preserving reagent mixed therewith may slow down the degradation of the biological molecule or its markers. While this method constitutes a substantial improvement over the smear paper devices of the past, unintended breakdown of the tip on top of the cap has occurred during manipulation or mailing of the specimen resulting in leakage and possible contamination. Moreover, specimens have a tendency to include excessive amounts of fecal material for the amount of preservative or reagent contained in the tube resulting in false positive analysis. Another improved device of the prior art is disclosed in U.S. Pat. No. 6,063,038 Diamond et al. In this case, a filtering membrane is provided between the body of the shipping vessel which holds the specimen and a preserving/reagent solution and the hollowed inside of the stick itself which can be accessed through a self-sealing membrane to extract a part of the liquid containing only the amount of specimen that passed through the filtering membrane. This improved device still suffers from a high risk of spillage of the preservative/reagent and a lack of quantitative mixing of the sample and preserving/reagent fluid.
Other devices provide for the dry storage of fecal material as disclosed in Kozak et al. U.S. Pat. No. 6,299,842 for purposes such as occult blood assays that detect labile exoantegens, but are not suited to carrying non-dry samples.
Because of the private and personal nature of fecal specimen collecting, collection is often performed by the relatively untrained donor. Further, because of the distasteful nature of feces, donors often have difficulty properly collecting or otherwise handling the fecal material. There is a need, therefore, for a device which reduces the handling of feces and the potential for close contact.
The instant invention results from some attempt to provide a practical solution to the problems and disadvantages of the aforesaid devices of the prior art.